Morphological and Structural Characterization of a Titanium Dioxide System

Alemany, Luı́s J.; Bañares, Miguel Á.; Pardo, Emilio; Martín-Jiménez, F. Javier; Blasco, J. M.

doi:10.1016/s1044-5803(99)00066-2

Cited by 43 publications

(38 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…21,22 These results are similar to those obtained earlier from 1 for reactions carried out in air. 16,17 In the present work, however, the sample IN700/HNO 3 still contains anatase at 700 °C, due to an incomplete anatase-rutile phase transition.…”

Section: In/hno 3 Samplessupporting

confidence: 90%

“…21,24 Finally, at 1000 °C, the spectrum contains well-defined rutile and low intensity ilmenite bands. 21,24 The Mössbauer spectra recorded for IN55-700/HNO 3 ( Figure 4) give Mössbauer parameters in the range for iron(III) oxides (Table 1). 25,26 Results for IN55/HNO 3 are compatible with the presence of amorphous Fe 2 O 3 in the sample.…”

Section: Synthesis Of Fe/ti Oxides From a Single Source Alkoxide Precmentioning

confidence: 99%

“…Only bands assignable to anatase and brookite are detected up to 300 °C, suggesting that trace amounts of brookite, not observed by XRD (Figure 2), are formed at these temperatures. 21 Bands for hematite appear at 500 °C, while those for a mixture of anatase, rutile, hematite and pseudobrookite are detected at 700 °C. 21,24 Finally, at 1000 °C, the spectrum contains well-defined rutile and low intensity ilmenite bands.…”

Section: Synthesis Of Fe/ti Oxides From a Single Source Alkoxide Precmentioning

confidence: 99%

“…21 Bands for hematite appear at 500 °C, while those for a mixture of anatase, rutile, hematite and pseudobrookite are detected at 700 °C. 21,24 Finally, at 1000 °C, the spectrum contains well-defined rutile and low intensity ilmenite bands. 21,24 The Mössbauer spectra recorded for IN55-700/HNO 3 ( Figure 4) give Mössbauer parameters in the range for iron(III) oxides (Table 1).…”

Section: Synthesis Of Fe/ti Oxides From a Single Source Alkoxide Precmentioning

confidence: 99%

“…Up to 300 °C, only reflections due to anatase TiO 2 can be observed. 21 The broad peaks suggest small average crystallite diameters, which were calculated as 4.5 and 5.4 nm for samples IN55/HNO 3 and IN300/ HNO 3 , respectively, according to Scherrer's law. Diffraction peaks for hematite (α-Fe 2 O 3 ) appear at 500 °C, 22 while the absence of peaks assignable to iron-based phases below this temperature may be due to an amorphous nature of the iron-containing species.…”

Section: In/hno 3 Samplesmentioning

confidence: 99%

See 4 more Smart Citations

Synthesis of Fe/Ti oxides from a single source alkoxide precursor under inert atmosphere

Camargo¹,

Nunes²,

Luis³

et al. 2008

J. Braz. Chem. Soc.

View full text Add to dashboard Cite

O alcóxido heterometálico [FeCl{Ti 2 (OPr i ) 9 }] (1) foi utilizado como um precursor de fonte única para a preparação de óxidos de Fe/Ti sob atmosfera inerte. Três procedimentos sintéticos distintos foram adotados no processamento de 1, com o emprego de soluções aquosas ácidas (HNO 3 ou HCl), ou na ausência de ácido mineral. Os produtos foram caracterizados por difratometria de raios X (pó), microscopia eletrônica de varredura combinada com espectroscopia de dispersão de raios X (MEV/EDS) e espectroscopias Raman, de ressonância paramagnética eletrônica (RPE) e Mössbauer. Os óxidos produzidos contêm titânio(IV) e ferro(III) (ou ferro(II)), dependendo das condições de reação e das temperaturas de tratamento térmico. Uma interessante redução de ferro(III) a ferro(II), que levou à obtenção de ilmenita (FeTiO 3 ), foi observada a 1000 o C no sistema contendo HNO 3 . Estudos por MEV/EDS revelaram uma distribuição altamente heterogênea dos metais em todos os produtos, possivelmente relacionada com a presença de um conteúdo significativo de carbono e de defeitos estruturais (vacâncias de oxigênio) nos sólidos.The heterometal alkoxide [FeCl{Ti 2 (OPr i ) 9 }] (1) was employed as a single source precursor for the preparation of Fe/Ti oxides under inert atmosphere. Three different synthetic procedures were adopted in the processing of 1, either employing aqueous HNO 3 or HCl solutions, or in the absence of mineral acids. Products were characterised by powder X-ray diffractometry, scanning electron microscopy combined with energy dispersive X-ray spectroscopy (SEM/EDS) and Raman, electron paramagnetic resonance (EPR) and Mössbauer spectroscopies. Oxide products contained titanium(IV) and either iron(III) or iron(II), depending on reaction conditions and thermal treatment temperatures. An interesting iron(III)→iron(II) reduction was observed at 1000 o C in the HNO 3 -containing system, leading to the detection of ilmenite (FeTiO 3 ). SEM/EDS studies revealed a highly heterogeneous metal distribution in all products, possibly related to the presence of a significant content of carbon and of structural defects (oxygen vacancies) in the solids.Keywords: oxides, sol-gel, single source precursor, inert atmosphere, electron microscopy IntroductionMultimetal oxide systems play an important role in materials science. They have been extensively investigated for the development of high performance ceramics and (nano)composites, aiming at applications in optics, electronics, magnetism and catalysis. The development of structural components, energy conversion devices, sensors and MRI contrast agents has also benefited from heterometal oxide research. [1][2][3][4] Nowadays, the preparation of these oxides is often performed by chemical methods. 3,[5][6][7] In particular, the sol-gel process, either hydrolytic or non-hydrolytic, has been widely employed due to its advantages over conventional solid state methods. These advantages include lower processing temperatures and better control over microstructure, uniformity and stoichiometry o...

show abstract

Section: In/hno 3 Samplessupporting

confidence: 90%

Section: Synthesis Of Fe/ti Oxides From a Single Source Alkoxide Precmentioning

confidence: 99%

Section: Synthesis Of Fe/ti Oxides From a Single Source Alkoxide Precmentioning

confidence: 99%

Section: Synthesis Of Fe/ti Oxides From a Single Source Alkoxide Precmentioning

confidence: 99%

Section: In/hno 3 Samplesmentioning

confidence: 99%

See 3 more Smart Citations

Synthesis of Fe/Ti oxides from a single source alkoxide precursor under inert atmosphere

Camargo¹,

Nunes²,

Luis³

et al. 2008

J. Braz. Chem. Soc.

View full text Add to dashboard Cite

show abstract

Evaluation of annealed titanium oxide nanotubes on titanium: From surface characterization to in vivo assays

Sanchez

Katunar

Pastore

et al. 2020

J Biomedical Materials Res

View full text Add to dashboard Cite

The entire route from anodic oxidation and surface characterization, including in vitro experiments and finally in vivo osseointegration assays were performed with the aim to evaluate nanotubular and crystalline annealed titanium oxides as a suitable surface for grade 2 titanium permanent implants. Polished titanium (T0) was compared with anodized surfaces obtained in acidic media with fluoride, leading to an ordered nanotubular structure of titanium oxide on the metal surface, characterized by tube diameter of 89 ± 24 nm (Tnts). Samples were thermally treated in air (TntsTT) to increase the anatase crystalline phase on nanotubes, with minor alteration of the structure. Corrosion tests were performed to evaluate the electrochemical response after 1, 14, and 28 days of immersion in simulated body fluid. Based on the in vitro results, heat‐treated titanium nanotubes (TntsTT) were selected as a promissory candidate to continue with the osseointegration in vivo assays. The in vivo results showed no major improvement in the osseointegration process when compared with untreated Ti after 30 days of implantation and there also was a lower increase in the development of new osseous tissue.

show abstract